Upgrading to an XMC-2, need 2 more channels, which amp(s)?

[brado]

I currently have  a 7.2 setup with my XMC-1, I am planning a 7.2.4 setup with the XMC-2. Here's my 7.2 setup in terms of amps:
* 3 XPA-1 Gen 2's for R/C/L
* 4 XPA-1L's for surounds and rear surround
* I also have 2 more XPA-1Ls that I will use for heights

So, I'm two channels short amp-wise.

I'm considering (in order of cost):
a) 1 XPA-2 Gen3 for the R/L surrounds, move the current XPA-1Ls to the heights (or just use the XPA for heights)  ($999)
b) 2 XPA HC-1 for for the R/L surrounds, move the current XPA-1Ls to the heights ($1398)
c) 1  XPA-DR2 for the R/L surrounds, move the current XPA-1Ls to the heights ($1599)
d) 2 XPA - DR1 for R/L, move the current XPA-1's to R/L surrounds ($2398)

Which option would you choose?

I'm happy with the XPA-1's for R/C/L. I'd be interested if anyone has any experience with both the XPA-1 G2 and the XPA-DR1 and could comment on sound quality differences to justify the cost differential from the other options mentioned.

thanks,
Brad